/* GIO - GLib Input, Output and Streaming Library * * Copyright (C) 2006-2007 Red Hat, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General * Public License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307, USA. * * Author: Alexander Larsson */ #include "config.h" #include #include #include #ifdef HAVE_UNISTD_H #include #endif #include #include #include #include #include "glibintl.h" #include "gioerror.h" #include "gcancellable.h" #include "glocalfileoutputstream.h" #include "glocalfileinfo.h" #ifdef G_OS_WIN32 #include #ifndef S_ISDIR #define S_ISDIR(m) (((m) & _S_IFMT) == _S_IFDIR) #endif #ifndef S_ISREG #define S_ISREG(m) (((m) & _S_IFMT) == _S_IFREG) #endif #endif #ifndef O_BINARY #define O_BINARY 0 #endif #include "gioalias.h" #define g_local_file_output_stream_get_type _g_local_file_output_stream_get_type G_DEFINE_TYPE (GLocalFileOutputStream, g_local_file_output_stream, G_TYPE_FILE_OUTPUT_STREAM); /* Some of the file replacement code was based on the code from gedit, * relicenced to LGPL with permissions from the authors. */ #define BACKUP_EXTENSION "~" struct _GLocalFileOutputStreamPrivate { char *tmp_filename; char *original_filename; char *backup_filename; char *etag; int fd; }; static gssize g_local_file_output_stream_write (GOutputStream *stream, const void *buffer, gsize count, GCancellable *cancellable, GError **error); static gboolean g_local_file_output_stream_close (GOutputStream *stream, GCancellable *cancellable, GError **error); static GFileInfo *g_local_file_output_stream_query_info (GFileOutputStream *stream, char *attributes, GCancellable *cancellable, GError **error); static char * g_local_file_output_stream_get_etag (GFileOutputStream *stream); static goffset g_local_file_output_stream_tell (GFileOutputStream *stream); static gboolean g_local_file_output_stream_can_seek (GFileOutputStream *stream); static gboolean g_local_file_output_stream_seek (GFileOutputStream *stream, goffset offset, GSeekType type, GCancellable *cancellable, GError **error); static gboolean g_local_file_output_stream_can_truncate (GFileOutputStream *stream); static gboolean g_local_file_output_stream_truncate (GFileOutputStream *stream, goffset size, GCancellable *cancellable, GError **error); static void g_local_file_output_stream_finalize (GObject *object) { GLocalFileOutputStream *file; file = G_LOCAL_FILE_OUTPUT_STREAM (object); g_free (file->priv->tmp_filename); g_free (file->priv->original_filename); g_free (file->priv->backup_filename); g_free (file->priv->etag); G_OBJECT_CLASS (g_local_file_output_stream_parent_class)->finalize (object); } static void g_local_file_output_stream_class_init (GLocalFileOutputStreamClass *klass) { GObjectClass *gobject_class = G_OBJECT_CLASS (klass); GOutputStreamClass *stream_class = G_OUTPUT_STREAM_CLASS (klass); GFileOutputStreamClass *file_stream_class = G_FILE_OUTPUT_STREAM_CLASS (klass); g_type_class_add_private (klass, sizeof (GLocalFileOutputStreamPrivate)); gobject_class->finalize = g_local_file_output_stream_finalize; stream_class->write_fn = g_local_file_output_stream_write; stream_class->close_fn = g_local_file_output_stream_close; file_stream_class->query_info = g_local_file_output_stream_query_info; file_stream_class->get_etag = g_local_file_output_stream_get_etag; file_stream_class->tell = g_local_file_output_stream_tell; file_stream_class->can_seek = g_local_file_output_stream_can_seek; file_stream_class->seek = g_local_file_output_stream_seek; file_stream_class->can_truncate = g_local_file_output_stream_can_truncate; file_stream_class->truncate_fn = g_local_file_output_stream_truncate; } static void g_local_file_output_stream_init (GLocalFileOutputStream *stream) { stream->priv = G_TYPE_INSTANCE_GET_PRIVATE (stream, G_TYPE_LOCAL_FILE_OUTPUT_STREAM, GLocalFileOutputStreamPrivate); } static gssize g_local_file_output_stream_write (GOutputStream *stream, const void *buffer, gsize count, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *file; gssize res; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); while (1) { if (g_cancellable_set_error_if_cancelled (cancellable, error)) return -1; res = write (file->priv->fd, buffer, count); if (res == -1) { int errsv = errno; if (errsv == EINTR) continue; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error writing to file: %s"), g_strerror (errsv)); } break; } return res; } static gboolean g_local_file_output_stream_close (GOutputStream *stream, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *file; GLocalFileStat final_stat; int res; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); #ifdef G_OS_WIN32 /* Must close before renaming on Windows, so just do the close first * in all cases for now. */ if (_fstati64 (file->priv->fd, &final_stat) == 0) file->priv->etag = _g_local_file_info_create_etag (&final_stat); res = close (file->priv->fd); if (res == -1) { int errsv = errno; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error closing file: %s"), g_strerror (errsv)); return FALSE; } #endif if (file->priv->tmp_filename) { /* We need to move the temp file to its final place, * and possibly create the backup file */ if (file->priv->backup_filename) { if (g_cancellable_set_error_if_cancelled (cancellable, error)) goto err_out; #ifdef HAVE_LINK /* create original -> backup link, the original is then renamed over */ if (g_unlink (file->priv->backup_filename) != 0 && errno != ENOENT) { int errsv = errno; g_set_error (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Error removing old backup link: %s"), g_strerror (errsv)); goto err_out; } if (link (file->priv->original_filename, file->priv->backup_filename) != 0) { /* link failed or is not supported, try rename */ if (g_rename (file->priv->original_filename, file->priv->backup_filename) != 0) { int errsv = errno; g_set_error (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Error creating backup copy: %s"), g_strerror (errsv)); goto err_out; } } #else /* If link not supported, just rename... */ if (g_rename (file->priv->original_filename, file->priv->backup_filename) != 0) { int errsv = errno; g_set_error (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Error creating backup copy: %s"), g_strerror (errsv)); goto err_out; } #endif } if (g_cancellable_set_error_if_cancelled (cancellable, error)) goto err_out; /* tmp -> original */ if (g_rename (file->priv->tmp_filename, file->priv->original_filename) != 0) { int errsv = errno; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errno), _("Error renaming temporary file: %s"), g_strerror (errsv)); goto err_out; } } if (g_cancellable_set_error_if_cancelled (cancellable, error)) goto err_out; #ifndef G_OS_WIN32 /* Already did the fstat() and close() above on Win32 */ if (fstat (file->priv->fd, &final_stat) == 0) file->priv->etag = _g_local_file_info_create_etag (&final_stat); while (1) { res = close (file->priv->fd); if (res == -1) { int errsv = errno; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error closing file: %s"), g_strerror (errsv)); } break; } return res != -1; #else return TRUE; #endif err_out: #ifndef G_OS_WIN32 /* A simple try to close the fd in case we fail before the actual close */ close (file->priv->fd); #endif return FALSE; } static char * g_local_file_output_stream_get_etag (GFileOutputStream *stream) { GLocalFileOutputStream *file; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); return g_strdup (file->priv->etag); } static goffset g_local_file_output_stream_tell (GFileOutputStream *stream) { GLocalFileOutputStream *file; off_t pos; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); pos = lseek (file->priv->fd, 0, SEEK_CUR); if (pos == (off_t)-1) return 0; return pos; } static gboolean g_local_file_output_stream_can_seek (GFileOutputStream *stream) { GLocalFileOutputStream *file; off_t pos; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); pos = lseek (file->priv->fd, 0, SEEK_CUR); if (pos == (off_t)-1 && errno == ESPIPE) return FALSE; return TRUE; } static int seek_type_to_lseek (GSeekType type) { switch (type) { default: case G_SEEK_CUR: return SEEK_CUR; case G_SEEK_SET: return SEEK_SET; case G_SEEK_END: return SEEK_END; } } static gboolean g_local_file_output_stream_seek (GFileOutputStream *stream, goffset offset, GSeekType type, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *file; off_t pos; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); pos = lseek (file->priv->fd, offset, seek_type_to_lseek (type)); if (pos == (off_t)-1) { int errsv = errno; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error seeking in file: %s"), g_strerror (errsv)); return FALSE; } return TRUE; } static gboolean g_local_file_output_stream_can_truncate (GFileOutputStream *stream) { /* We can't truncate pipes and stuff where we can't seek */ return g_local_file_output_stream_can_seek (stream); } static gboolean g_local_file_output_stream_truncate (GFileOutputStream *stream, goffset size, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *file; int res; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); restart: #ifdef G_OS_WIN32 res = g_win32_ftruncate (file->priv->fd, size); #else res = ftruncate (file->priv->fd, size); #endif if (res == -1) { int errsv = errno; if (errsv == EINTR) { if (g_cancellable_set_error_if_cancelled (cancellable, error)) return FALSE; goto restart; } g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error truncating file: %s"), g_strerror (errsv)); return FALSE; } return TRUE; } static GFileInfo * g_local_file_output_stream_query_info (GFileOutputStream *stream, char *attributes, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *file; file = G_LOCAL_FILE_OUTPUT_STREAM (stream); if (g_cancellable_set_error_if_cancelled (cancellable, error)) return NULL; return _g_local_file_info_get_from_fd (file->priv->fd, attributes, error); } GFileOutputStream * _g_local_file_output_stream_create (const char *filename, GFileCreateFlags flags, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *stream; int mode; int fd; if (g_cancellable_set_error_if_cancelled (cancellable, error)) return NULL; if (flags & G_FILE_CREATE_PRIVATE) mode = 0600; else mode = 0666; fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY | O_BINARY, mode); if (fd == -1) { int errsv = errno; if (errsv == EINVAL) /* This must be an invalid filename, on e.g. FAT */ g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_INVALID_FILENAME, _("Invalid filename")); else { char *display_name = g_filename_display_name (filename); g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error opening file '%s': %s"), display_name, g_strerror (errsv)); g_free (display_name); } return NULL; } stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL); stream->priv->fd = fd; return G_FILE_OUTPUT_STREAM (stream); } GFileOutputStream * _g_local_file_output_stream_append (const char *filename, GFileCreateFlags flags, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *stream; int mode; int fd; if (g_cancellable_set_error_if_cancelled (cancellable, error)) return NULL; if (flags & G_FILE_CREATE_PRIVATE) mode = 0600; else mode = 0666; fd = g_open (filename, O_CREAT | O_APPEND | O_WRONLY | O_BINARY, mode); if (fd == -1) { int errsv = errno; if (errsv == EINVAL) /* This must be an invalid filename, on e.g. FAT */ g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_INVALID_FILENAME, _("Invalid filename")); else { char *display_name = g_filename_display_name (filename); g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error opening file '%s': %s"), display_name, g_strerror (errsv)); g_free (display_name); } return NULL; } stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL); stream->priv->fd = fd; return G_FILE_OUTPUT_STREAM (stream); } static char * create_backup_filename (const char *filename) { return g_strconcat (filename, BACKUP_EXTENSION, NULL); } #define BUFSIZE 8192 /* size of normal write buffer */ static gboolean copy_file_data (gint sfd, gint dfd, GError **error) { gboolean ret = TRUE; gpointer buffer; const gchar *write_buffer; gssize bytes_read; gssize bytes_to_write; gssize bytes_written; buffer = g_malloc (BUFSIZE); do { bytes_read = read (sfd, buffer, BUFSIZE); if (bytes_read == -1) { int errsv = errno; if (errsv == EINTR) continue; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error reading from file: %s"), g_strerror (errsv)); ret = FALSE; break; } bytes_to_write = bytes_read; write_buffer = buffer; do { bytes_written = write (dfd, write_buffer, bytes_to_write); if (bytes_written == -1) { int errsv = errno; if (errsv == EINTR) continue; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error writing to file: %s"), g_strerror (errsv)); ret = FALSE; break; } bytes_to_write -= bytes_written; write_buffer += bytes_written; } while (bytes_to_write > 0); } while ((bytes_read != 0) && (ret == TRUE)); g_free (buffer); return ret; } static int handle_overwrite_open (const char *filename, const char *etag, gboolean create_backup, char **temp_filename, GCancellable *cancellable, GError **error) { int fd = -1; GLocalFileStat original_stat; char *current_etag; gboolean is_symlink; int open_flags; int res; /* We only need read access to the original file if we are creating a backup. * We also add O_CREATE to avoid a race if the file was just removed */ if (create_backup) open_flags = O_RDWR | O_CREAT | O_BINARY; else open_flags = O_WRONLY | O_CREAT | O_BINARY; /* Some systems have O_NOFOLLOW, which lets us avoid some races * when finding out if the file we opened was a symlink */ #ifdef O_NOFOLLOW is_symlink = FALSE; fd = g_open (filename, open_flags | O_NOFOLLOW, 0666); if (fd == -1 && errno == ELOOP) { /* Could be a symlink, or it could be a regular ELOOP error, * but then the next open will fail too. */ is_symlink = TRUE; fd = g_open (filename, open_flags, 0666); } #else fd = g_open (filename, open_flags, 0666); /* This is racy, but we do it as soon as possible to minimize the race */ is_symlink = g_file_test (filename, G_FILE_TEST_IS_SYMLINK); #endif if (fd == -1) { int errsv = errno; char *display_name = g_filename_display_name (filename); g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error opening file '%s': %s"), display_name, g_strerror (errsv)); g_free (display_name); return -1; } #ifdef G_OS_WIN32 res = _fstati64 (fd, &original_stat); #else res = fstat (fd, &original_stat); #endif if (res != 0) { int errsv = errno; char *display_name = g_filename_display_name (filename); g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error stating file '%s': %s"), display_name, g_strerror (errsv)); g_free (display_name); goto err_out; } /* not a regular file */ if (!S_ISREG (original_stat.st_mode)) { if (S_ISDIR (original_stat.st_mode)) g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_IS_DIRECTORY, _("Target file is a directory")); else g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_NOT_REGULAR_FILE, _("Target file is not a regular file")); goto err_out; } if (etag != NULL) { current_etag = _g_local_file_info_create_etag (&original_stat); if (strcmp (etag, current_etag) != 0) { g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_WRONG_ETAG, _("The file was externally modified")); g_free (current_etag); goto err_out; } g_free (current_etag); } /* We use two backup strategies. * The first one (which is faster) consist in saving to a * tmp file then rename the original file to the backup and the * tmp file to the original name. This is fast but doesn't work * when the file is a link (hard or symbolic) or when we can't * write to the current dir or can't set the permissions on the * new file. * The second strategy consist simply in copying the old file * to a backup file and rewrite the contents of the file. */ if (!(original_stat.st_nlink > 1) && !is_symlink) { char *dirname, *tmp_filename; int tmpfd; dirname = g_path_get_dirname (filename); tmp_filename = g_build_filename (dirname, ".goutputstream-XXXXXX", NULL); g_free (dirname); tmpfd = g_mkstemp (tmp_filename); if (tmpfd == -1) { g_free (tmp_filename); goto fallback_strategy; } /* try to keep permissions */ if ( #ifdef HAVE_FCHOWN fchown (tmpfd, original_stat.st_uid, original_stat.st_gid) == -1 || #endif #ifdef HAVE_FCHMOD fchmod (tmpfd, original_stat.st_mode) == -1 || #endif 0 ) { struct stat tmp_statbuf; /* Check that we really needed to change something */ if (fstat (tmpfd, &tmp_statbuf) != 0 || original_stat.st_uid != tmp_statbuf.st_uid || original_stat.st_gid != tmp_statbuf.st_gid || original_stat.st_mode != tmp_statbuf.st_mode) { close (tmpfd); g_unlink (tmp_filename); g_free (tmp_filename); goto fallback_strategy; } } close (fd); *temp_filename = tmp_filename; return tmpfd; } fallback_strategy: if (create_backup) { #if defined(HAVE_FCHOWN) && defined(HAVE_FCHMOD) struct stat tmp_statbuf; #endif char *backup_filename; int bfd; backup_filename = create_backup_filename (filename); if (g_unlink (backup_filename) == -1 && errno != ENOENT) { g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Backup file creation failed")); g_free (backup_filename); goto err_out; } bfd = g_open (backup_filename, O_WRONLY | O_CREAT | O_EXCL | O_BINARY, original_stat.st_mode & 0777); if (bfd == -1) { g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Backup file creation failed")); g_free (backup_filename); goto err_out; } /* If needed, Try to set the group of the backup same as the * original file. If this fails, set the protection * bits for the group same as the protection bits for * others. */ #if defined(HAVE_FCHOWN) && defined(HAVE_FCHMOD) if (fstat (bfd, &tmp_statbuf) != 0) { g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Backup file creation failed")); g_unlink (backup_filename); g_free (backup_filename); goto err_out; } if ((original_stat.st_gid != tmp_statbuf.st_gid) && fchown (bfd, (uid_t) -1, original_stat.st_gid) != 0) { if (fchmod (bfd, (original_stat.st_mode & 0707) | ((original_stat.st_mode & 07) << 3)) != 0) { g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Backup file creation failed")); g_unlink (backup_filename); close (bfd); g_free (backup_filename); goto err_out; } } #endif if (!copy_file_data (fd, bfd, NULL)) { g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_CANT_CREATE_BACKUP, _("Backup file creation failed")); g_unlink (backup_filename); close (bfd); g_free (backup_filename); goto err_out; } close (bfd); g_free (backup_filename); /* Seek back to the start of the file after the backup copy */ if (lseek (fd, 0, SEEK_SET) == -1) { int errsv = errno; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error seeking in file: %s"), g_strerror (errsv)); goto err_out; } } /* Truncate the file at the start */ #ifdef G_OS_WIN32 if (g_win32_ftruncate (fd, 0) == -1) #else if (ftruncate (fd, 0) == -1) #endif { int errsv = errno; g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error truncating file: %s"), g_strerror (errsv)); goto err_out; } return fd; err_out: close (fd); return -1; } GFileOutputStream * _g_local_file_output_stream_replace (const char *filename, const char *etag, gboolean create_backup, GFileCreateFlags flags, GCancellable *cancellable, GError **error) { GLocalFileOutputStream *stream; int mode; int fd; char *temp_file; if (g_cancellable_set_error_if_cancelled (cancellable, error)) return NULL; temp_file = NULL; if (flags & G_FILE_CREATE_PRIVATE) mode = 0600; else mode = 0666; /* If the file doesn't exist, create it */ fd = g_open (filename, O_CREAT | O_EXCL | O_WRONLY | O_BINARY, mode); if (fd == -1 && errno == EEXIST) { /* The file already exists */ fd = handle_overwrite_open (filename, etag, create_backup, &temp_file, cancellable, error); if (fd == -1) return NULL; } else if (fd == -1) { int errsv = errno; if (errsv == EINVAL) /* This must be an invalid filename, on e.g. FAT */ g_set_error_literal (error, G_IO_ERROR, G_IO_ERROR_INVALID_FILENAME, _("Invalid filename")); else { char *display_name = g_filename_display_name (filename); g_set_error (error, G_IO_ERROR, g_io_error_from_errno (errsv), _("Error opening file '%s': %s"), display_name, g_strerror (errsv)); g_free (display_name); } return NULL; } stream = g_object_new (G_TYPE_LOCAL_FILE_OUTPUT_STREAM, NULL); stream->priv->fd = fd; stream->priv->tmp_filename = temp_file; if (create_backup) stream->priv->backup_filename = create_backup_filename (filename); stream->priv->original_filename = g_strdup (filename); return G_FILE_OUTPUT_STREAM (stream); }